It's rare that we see a truly original idea in a video game. Rock of Ages, however, gives the world something it has never seen before: A bizarre hybrid of platforming, racing, and tower defense. While the game doesn't have as much of a fun factor as it could, it's enjoyable to play, and the developers' creativity deserves to be celebrated.

As the single-player story mode begins, you're introduced to Sisyphus, a king from Greek mythology. As a punishment, Sisyphus had to roll a boulder up a hill, watch it roll down, and start again, repeating this task throughout eternity. But something's not quite right here: Whenever the time comes for the boulder to roll back down, a demon sneaks up on Sisyphus, looking like Dennis the Menace, and pokes him in the rear end with a stick, startling the king into letting the boulder go.

In this retelling, Sisyphus gets sick of his punishment. He decides to kill his captor with the boulder. And that's when your first match begins.

In Rock of Ages, your goal is to break down the opposing team's castle door and kill their leader before they can do the same to you. You do this by controlling Sisyphus's boulder, navigating it along a complicated obstacle course and slamming it into the door with as much force as possible. You can even make the boulder jump, which adds a platforming element. And because most doors will take exactly three hits to fall down, the goal is to get to get those three hits in as quickly as possible, making it feel like a race.

Once you smash a boulder into the opposing team's door, it takes your team a little while to make another one. During this time, you can spend your cash—some of which you start with, some of which you earn by knocking down obstacles on the way to the other team's door. Rock of Ages gives you a variety of tools to work with, including towers that block the opponent as he tries to pass, slingshots that try to blast him off course, dynamite barrels that act as mines, and even cattle that will push him around if he gets too close. If you use these items strategically, you can delay your opponent significantly, giving you an advantage when it comes to hitting the door first.

You can also spend money upgrading your rock before your next run—making it red-hot, for example, or protecting it with spiky metal strips. These protections wear off as you run into obstacles, but if you make it all the way to the door with them still intact, you deal an incredible amount of damage. If you can manage to do this twice, you just might knock the door down on the second hit, which is basically a guaranteed win.

As the game wears on, you encounter several different periods in time, making the game a sort of Bizarro World tour of history and mythology. The cutscenes are always amusing, mixing the academic subject matter with pop-culture references (including Castlevania and the movie 300).

The story mode isn't all the game has to offer. There's also Skeeball, in which the tower defense element of the game disappears. Instead, you have to destroy as many obstacles as possible on the way to the goal, and then jump into a set of holes, aiming for the one that gives you the highest multiplier. (This mode is named after skee ball, also known as "that game at Chuck E. Cheese where you roll a ball down a lane and then it jumps onto a board with point totals on it.") In addition, there's a basic time-trial mode.

There is also split-screen and online multiplayer, including both standard matches and Skeeball competitions. Unfortunately, I wasn't able to find any matches online when I tried, but the split-screen component worked very well for me. I imagine that many players will find this highly addictive.